The Only One
by McShipper
Summary: Erin is forced to go to her mothers wedding and she needs some moral support in the form of Jay Halstead. Laughing, dancing, drinking and other events will ensue. Rated T(Possibly rated M in the future, be sure to favorite so you are updated when i post new chapters :0)


**A/N: I AM SO EXCITED ABOUT THIS FIC. Me and another amazing author on here, BaeHalstead, came up with this idea on tumblr and we are both running for it. I cannot wait to read her version of it, she is an amazing writer and I encourage you strongly to go check out her stuff. :3 **

**SOOOO I started writing this before Wednesdays episode, which I loved certain parts of, but I was thoroughly disappointed because of the lack of linstead, I expected a little more. It also ruined the timeline of this fic, but oh well. This takes place a few weeks after the bounty has been placed on Halsteads pretty little head. **

**The story is named after a song called 'The Only One' by James Blunt, it just fit and that's why I chose it. It will reoccur throughout the story. For those of you who don't read my other stuff, well…do it. But please please be understanding and patient with me because I have a chronic illness that leaves me in a lot of pain aka not able to write. Updates will not be planned or timely but I can promise that they will be good. **

***Friendly reminder that I do not own any of these characters, unfortunately. * **

**I've actually been working on this for a few weeks now so I really hope that you all enjoy it. I haven't really proof read some of it, so please forgive any dumb mistakes, I will fix them eventually. Happy reading! **

Erin's phone vibrates against the glass of her living room table, interrupting the 'Hawks game, _again_.

Jay leans over the table and lets out a chuckle, "Erin, that's the third time your phone has gone off in the last ten minutes," Jay says, taking a pull of his beer. "If she calls again, I'm throwing the phone out the window."

'Demanding, Check.' Erin thinks to herself, adding another item to the con side of her mental list; her list of the pros and cons of living with Detective Jay Halstead. To her dismay, the Pros still outweigh the cons. Erin honestly doesn't want to admit to herself how much she enjoys him being in her apartment every day, even if he does leave his dirty socks all over the place.

Erin sticks her tongue out at him and leans over to grab her phone. She lets out a sigh and presses answer.

"Mom, what do you want?" She says as she gets up from her spot on the couch. "Well I'm busy mom, sorry."

Erin groans inwardly as she listens, "No mom," she says, " I already told you, I'm not coming to the wedding."

"Yes mom, I do want you back in my life." She rolls her eyes as she listens to her mother's voice whine into her ear. "Fine! Fine, I'll come. Just stop crying mom, ok?"

"Wait…You WHAT?" She bellows into the phone, "Why would you do that mom?"

She sighs again as Bunny drones on in her ear, "Fine! I'll make it work, I'll figure it out. Yeah, I'll talk to you later. Bye."

Erin collapses exhaustedly back onto the couch, and holds her hand out, waiting for Jay to pass over his beer.

Jay chuckles as he hands her his bottle. He watches her guzzle the rest of the brew and he raises his eyebrows, "So It went well?"

Erin snorts and hands him the empty bottle, "That's the understatement of the century." She says as she reaches for a piece of cold pizza. "She guilted me into going to her wedding. She swears that he's 'the one'." Erin rolls her eyes as the words leave her mouth.

"And you've heard that one before." Jay gathers as he takes the pizza from Erin, feeling a sudden pang of hunger himself.

Erin slaps Jay on the thigh as she finishes chewing her mouthful of pizza, "Not only that," She says sitting up and turning to face him, "She also told her 'husband to be' that the reason I'm so busy and never see her is because I'm _married_."

Jay nearly chokes on his pizza as laughter bubbles up from deep in his gut. Seeing him laugh, Erin can't help but giggle as well.

"_Seriously_?" He asks, laughing so hard he can hardly get the word out.

Erin scrunches her face, grabs a pillow and whacks him with it. "It's not _that _funny, Halsted." She hits him again before reaching for the remote, turning the volume up on the hockey game.

"Besides," She says laying back and stretching her feet over his lap, "who do you think is going to be my husband?"

* * *

><p>Two weeks later Erin is standing barefoot in her bathroom with half of her hair done up in curlers.<p>

"Why am I doing this?" She mumbles as she runs her brush through a chunk of her hair. She stops and looks at herself in the mirror, feeling silly for thinking this was a good idea in the first place. She slams her brush down onto her tiled counter and storms her bedroom.

"Why am I doing this?" She says again, loud enough to make Jay jump. He turns to look at her and sees panic in her eyes.

Jay tries not to seem shocked by her appearance. Her hair is half up in curlers, the other half hangs loose around her shoulders and she stands in her robe, which is dangerously short. Standing there looking at her all panicked and rage-y with her hands on her hips, he has to suppress the smile that is tugging at his lips. "Why are you doing what?"

"Going to the wedding! Placating my mother! I mean seriously, all she has ever done is use me. It's not like she really wants me there, she just wants it to look good. She's so fake, I can't stand it." Erin runs her hands over her face, "I'm just so sick of her games. I don't know why I'm doing this."

Jay isn't sure why she's doing it either. He's heard stories about her mother and from what he's heard; the woman doesn't deserve another minute of Erin's time. But that isn't what she needs to hear right now.

"Erin," Jay says placing his hands on her arms, "Under your tough badass exterior, you are one of the kindest hearted people I know. You're giving her another chance because you want to see the good in her, because you like to find the good in people. That's just the kind of person you are. "

She locks eyes with him, surprised by the words that just left his mouth. She holds his gaze for a moment, maybe for a moment too long. Her eyes wander down his body. Her partner looks incredibly good standing there in his suit pants and his white undershirt, _too_ good. It takes all of her willpower not to run her hands over his muscles. She shakes her head, willing the thoughts from her head before her eyes travel back up to his.

"What if she hurts me again?" Erin whispers, her voice cracking; her vulnerability shining through the tears in her eyes.

Jay lets out a sad sigh and pulls her into a solid hug. He feels her body relax as her arms curl around him. He rests his chin on her head.

"That's the shitty thing, there is no saying that she won't hurt you again, or use you again, or play games with you again. One thing I do know though is that you are the better person for giving her another chance. "Jay says into her hair. He feels her sigh against him and he gives her a squeeze. "Just get through tonight. I'll be there; I'll cover your six." He says, earning a laugh from her.

"I'm sure you will." She murmurs into his shirt.

"I'm serious; I'll get you out of there if you need me too. We can have a safe word." He says enthusiastically, trying to lighten her mood.

"A safe word?" Erin pulls away to look at him. He gives her a smirk and she raises an eyebrow at him. "We're going to a wedding Halstead, not your sex dungeon. "

"You wish." He scoffs, jokingly.

"No, you wish." Erin taunts back.

'_We both wish'_ Jay thinks to himself but bites his tongue to refrain from saying it. Yet the unspoken words seem to linger in the air between them. He raises his eyebrow at her, knowingly riling her up. "So, what's our safe word?"

"Pie." Erin volunteers, almost automatically.

"_Pie_?" Jay asks, letting out a laugh.

"Everybody loves pie!" She says, defending her choice. Jay just laughs harder, which makes her want to laugh as well but she fights to keep her composure.

"_What?_" She asks, exasperated when he won't stop laughing.

"This is good." He says, catching his breath. "This tells me a lot about you."

Erin responds by shoving his shoulder before crossing her arms over her chest, feigning anger.

"Pie it is." Jay says matter of factly, making the smile that Erin was suppressing escape.

"I win." She says smugly.

"Don't get used to it." Jay says, a hint of dominance in his voice.

"Is that an order?" Erin rebuts.

"No, it's a threat." Jay confirms with a bit of the devil in his eye. "Now go get ready, _that_ is an order."

"Yes sir." She mockingly salutes him before trudging her bare feet back to the bathroom.

* * *

><p>If you put a gun to Erin Lindsay's head at this very moment and asked her what her greatest weakness was it would be an easy answer; men in nice suits. Seeing a man in a suit always made Erin tingle from her toes to the top of her head. That feeling only intensified when she saw her partner in a suit for the first time, when he almost escorted her to her high school reunion. She had been so weak that she almost went home with him that night; it took everything she had not to give into the tingle.<p>

Erin looks at herself in the mirror as she puts in her second earring. She wills herself not to get caught up by seeing Jay in a suit again. With the drama of her mother's wedding and a lot more alcohol likely to be in play, she wasn't sure she'd be as strong this time. 'Thank god I shaved my legs,' she thinks to herself before mentally scolding herself. 'Get a grip Erin, you can't go there.' She pep talks herself in the mirror. The thing is it wasn't the threat Voight has hanging over Jay's head that was stopping her. It was the fact that she would like it too much, that she would _feel_ too much.

She takes one last look in the mirror and takes a deep breath. "You can do this." She whispers to herself. She sets her shoulders back and saunters into her living room.

Jay Is standing in Erin's living room looking at a picture on her bookshelf. When he hears her footsteps on the hardwood he spins around. When he sees her he feels like he's been punched in the gut, in a good way. She looks good, _too_ good. Her hair is curly and loose around her bare shoulders. She's wearing a matte corset topped black dress that turns into sheer billowy fabric, which dances around her knees. Her heels set her at about his height and make Erin's legs look about a million miles long. It takes every ounce of Jay's willpower not push her against the wall and kiss the hell out of her. Instead, he lets out a long slow whistle.

Erin smirks, "Oh look, he does have nice suits." She comments sarcastically.

"Yeah yeah," Jay says, jokingly rolling his eyes before looking at her seriously, "You look gorgeous Erin."

Jays words and the tone of his voice make Erin's heart skip. She bites her lip before murmuring a soft thank you. The feelings inside of her scream at her to cross the room and kiss him but she knows that if she did, she wouldn't stop. She does cross the room, just wanting to be in closer proximity to him.

"What were you looking at?" She asks, motioning to the bookshelf full of books, knickknacks, and pictures.

Jay thumbs in the direction of her favorite picture. "This is my favorite picture of us." He says with a smile on his face, remembering how happy he had been that night.

The picture was one of the entire unit, they had been drinking at Molly's and someone, probably Kim, had decided it was selfie time. Erin had wrapped her arms around Jay's neck and he had possessively put his arm around her before he pulled her into him at the hip.

"It's my favorite too." She says with a wide smile, her dimples showing.

"Oh I have something for you." He reaches into his pocket and pulls out a black box. "I figured since we're supposed to be married…"

Erin's right eyebrow shoots up, "You got me a ring Halstead?" He just shrugs. "How much did you spend on it, thirty five bucks at Wal-Mart?"

Jay smirks, "Actually it was my grandmothers." He says as he flips the box open.

Erin gasps and her hand wraps around his forearm as she admires the ring. "Holy Shit." She whispers. In the box is a princess cut aquamarine stone, encrusted around it are two bands of what look like chocolate diamonds. Her heart is racing, and she's not sure if it's a side effect of seeing the gorgeous or the gorgeous piece of jewelry or the fact that _Jay Halstead_ got her a ring. "Diamonds?" She asks a little breathlessly.

"Yup." Jay says, amused by her reaction. But he intends to show her mother that Erin Lindsay deserves the best. Come hell or high water he would make sure she gets it. He grasps her hand and slowly slides the ring on with ease.

"I can't imagine how many girls have worn this." Erin says with a laugh, trying to use humor to mask her real emotions, which are frenetically pumping through her veins. His gentle grip is still around her wrist, she prays to god that he can't feel her wild pulse.

Jay smirks for a moment but his face turns serious as he locks eyes with her. "Just you." He says simply. "You are the only one."

Erin involuntarily takes a sharp intake of breath at his words, which linger in the space between them.

She takes a deep breath and reigns in her emotions, hoping that when she speaks her voice won't fail her. "Thank you, for being here for me, for all of this. " She says sincerely, emotion in her voice.

"Of course, you deserve the best." He says with a hint of a smile. He offers her his arm, "We should go."

"Yes, we should." Erin says, looping her arm through his. She was suddenly looking forward to the wedding, and to Jay Halstead being her husband for the night.

* * *

><p>"The Plaza." Erin scoffs as they walk into the lavish banquet room. "This feels like an alternate reality. I'm pretty sure my mother's last wedding happened in Atlantic city when she was coked out of her brain. She threw up on the priest" Jay raises an eyebrow at her, "She did, I saw pictures." Erin says with a snort.<p>

"I wonder how she swung this one. " Jay wonders aloud.

"She probably conned somebody out of it, knowing her." Erin remarks.

"Erin, Darling! " Bunny's voice carries making Jay cringe and Erin roll her eyes.

"Here we go," Erin mutters under her breath.

"Erin, I'm so glad _your husband_ could make it." Bunny says a little too enthusiastically, gripping on to her new husbands arm. "This is Jeff, Erin's husband." She tells her new groom.

"It's Jay. " Erin snaps, correcting her.

Jay can feel the tension rising in his partner. He lightly runs his fingers down the underside of her arm and slips his hand down to interlace his fingers with hers.

"We have rooms booked upstairs for family, so feel free to grab one of those. I expect to see you at brunch in the morning. "

"We'll see mom, we both have very busy schedules." Erin says, knowing that her excuse probably won't cut it.

"Erin this is my special day, I want to have you with me." Her mother whines.

Jay gives Erin's hand a reassuring squeeze and rubs his thumb against her skin. Erin enjoys the warmth that spreads through her body, and the security.

"Alright mom, we'll go to brunch."

"That means a lot to us." Her mother's new husband offers. "We're really glad you both could make it." He comments, making sure to emphasize the both of them.

"Oh darling, there's Kendra," Erin's mother says, disengaging from the conversation. "She's the one that got us the gorgeous gravy boat; we just have to thank her." Bunny pulls her husband away in the direction of the crowd.

Jay blows out a relieved breath, "Wow." He says, clearly shocked by his first impression of Erin's mother. "You clearly got absolutely none of your attributes from her."

"She's so fake, it's disgusting." Erin scoffs.

"Hey don't worry, there's an upside to coming." Jay says motioning to his left, knowing exactly what Erin needs at the moment. "Open bar."

"Thank God," Erin murmurs. "I need a drink."

**A/N: SOOOOO WHAT DO YOU THINK? YES OR YIKES? This is definitely going to be multichapter and I promise we will get to some good stuff next chapter, I didn't want to rush this one. ;) I hope that you guys liked it, please favorite, follow, and give me some feedback in the comments? It means the world to me. :3 3**


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